State   A state is a condition or phase, in the lifetime of a classifier instance, during which it can be observed for a finite amount of time and has a particular condition.

Explanation

A running system interacts with its internal and external environment and changes in response to events including the passage of time. Some changes are significant or of interest to the modeler. When a system changes it is because some of its parts change. A state models the discrete condition, action or waiting of interest that an instance can be in either during its whole lifetime or within an interaction it participates in. The state may represent the fact that the instance: satisfies a condition or set of conditions, is performing some action, or is waiting for an event to occur, the event may be internal or external What is significant is that the condition must be of interest or relevant to the overall model. A state can contain activities, which are performed at specific times indicated by keywords as follows:

• entry activity - which is performed when the state is entered
• exit activity - which is performed upon exit from the state
• do activity - which is performed continuously while the modeled element is in the state or until the activity is completed.

Related Entries

Action  Graphically Similar,  Confused with An activity or action state as it is more formally called, is essentially a simplified type of state with a single entry action. An activity must have at least one outgoing transition. The activity is not influenced by internal or external events; as soon as the entry action (or work) of the activity is complete an outgoing transition is fired.